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    Subject[PATCH AUTOSEL 5.4 14/50] arm/ftrace: Fix BE text poking
    Date
    From: Peter Zijlstra <peterz@infradead.org>

    [ Upstream commit be993e44badc448add6a18d6f12b20615692c4c3 ]

    The __patch_text() function already applies __opcode_to_mem_*(), so
    when __opcode_to_mem_*() is not the identity (BE*), it is applied
    twice, wrecking the instruction.

    Fixes: 42e51f187f86 ("arm/ftrace: Use __patch_text()")
    Reported-by: Dmitry Osipenko <digetx@gmail.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Tested-by: Dmitry Osipenko <digetx@gmail.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/arm/kernel/ftrace.c | 7 ++-----
    1 file changed, 2 insertions(+), 5 deletions(-)

    diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
    index bda949fd84e8b..93caf757f1d5d 100644
    --- a/arch/arm/kernel/ftrace.c
    +++ b/arch/arm/kernel/ftrace.c
    @@ -81,13 +81,10 @@ static int ftrace_modify_code(unsigned long pc, unsigned long old,
    {
    unsigned long replaced;

    - if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
    + if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
    old = __opcode_to_mem_thumb32(old);
    - new = __opcode_to_mem_thumb32(new);
    - } else {
    + else
    old = __opcode_to_mem_arm(old);
    - new = __opcode_to_mem_arm(new);
    - }

    if (validate) {
    if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))
    --
    2.20.1
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